This proposal outlines a series of nuclear magnetic resonance (NMR) experiments that are designed to provide quantitative information about the 3-dimensional structures and functions of peptides in lipid-bilayers and to gain insight into the molecular events of membrane transport processes. In one series of experiments 1H-NMR techniques will be used to investigate the kinetics of ion-peptide interactions and the conformational properties of a model membrane system in which the cation-transport antibiotic, valinomycin or one of its several synthetic peptide analogues are incorporated into sonicated dispersion of fully deuterated phospholipids. The conformational and kinetic properties will be determined as functions of the primary structure of the peptide and the size of the cation. In a second series of experiments, 2H-NMR will be used to provide new ways for characterizing the configurations and dynamics of H-bonding in peptides. In these experiments, the effects of H-bonding on the relaxation times, the quadrupole coupling constants and electric field gradients of deuterium in amide sites will be determined from 2HNMR studies on deuterated peptides in solution, in oriented samples and in the solid state. From the experience and information gained in these studies, it is hoped that the technique may be extended eventually to study the structure and orientation of peptides in membrane bilayers as well.